A standard stackable chair comprises a frame typically made of aluminum or steel tubing and having four floor-engaging legs, a generally horizontal seat, and a generally vertical back. The frames are constructed so that the chairs can be stacked atop one another for storage and transport. Such chairs may also each be equipped with one or two arms.
In order to form orderly rows of such chairs, it is known to provide them with coupling members that allow them to be interlocked one next to the other. With armless chairs such coupling is fairly simple. When the chairs have one arm each, it is possible to form a row with one arm between adjacent chairs. Alternately chairs with two arms can be alternated with armless chairs.
The problem with this system is that stacking the arm chairs, that is the chairs equipped with one or two arms, is somewhat complex, especially when these chairs are also equipped with the above-mentioned coupling members. Accordingly German utility model 89 10 779 describes a system with removable arms. Thus the arms are taken off so that the chairs can be stacked and put back on again when the chairs are to be used. Once the rows are built, the arms are reinstalled. This is obviously an unsatisfactory solution as it requires extra work to take down and set up the chairs, and offers the opportunity to lose the arms when they are separated from the chairs.
Thus German patent 3,933,817 describes a system where chairs having permanent arms are interlocked in rows by means of retractable coupling hooks mounted underneath the seats. These hooks are pulled out to couple the chairs together and pushed back in when they are to be stacked, avoiding the problem of the coupling hooks interfering with the stacking. These coupling hooks have to be differently constructed for arm and armless chairs and add considerably to the cost of the chair. Furthermore if they are not properly retracted, they interfere with stacking, so this solution is also unsatisfactory.
In German patent 3,110,050 the chairs have arms that can be pivoted out of the way for stacking the chairs. Once again this entails an extra operation both on putting away and setting up the chairs, and the pivot structure adds somewhat to the cost of the chairs.
Thus in all the known solutions the arms and/or the coupling elements must be displaced to allow the chairs to stack. Furthermore interconnecting armless chairs with arm chairs is often difficult or impossible, and of course stacking different types of chairs is similarly out of the question.